alt Hacker NewsSpeculation:
1) This could actually be an attempt to gain more revenue from big customers that have users who use the free version to test that code can synthesize and run unit tests (by pretending to use smaller parts), and then only use the paid version for the final integration into the actual larger parts.
2) This could give them more customer data more easily. They make no secret of the fact that the free tiers share data with the mothership for product improvement reasons. Maybe they only want to maintain the infrastructure to do this on Windows, or maybe it's harder for customers to subvert on Windows.
3) There will be people running the Windows version on Linux, and explaining how to do it, in 3... 2... 1...
Are the prices so insane this is actually a viable option instead of just buying a bigger license? I always tell juniors to just submit a request for a licence since it will likely cost far less than retraining them or making them work harder and more to compensate for splitting things up (not FPGA related though).